76th Annual Meeting of the APS Division of Fluid Dynamics (November 19, 2023 — November 21, 2023)

P0011: Lab icebergs melt down and flip out

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Authors

• Bobae Johnson, New York University, Courant Institute, Applied Math Lab
• Steven Zhang, New York University, Courant Institute, Applied Math Lab
• Alison Kim, New York University, Courant Institute, Applied Math Lab
• Scott Weady, New York University, Courant Institute, Applied Math Lab
• Leif Ristroph, New York University, Courant Institute, Applied Math Lab

DOI: https://doi.org/10.1103/APS.DFD.2023.GFM.P0011

The behavior of ice is  a symptom of our planet’s health. Natural ice is dynamic, growing, shrinking and breaking off as icebergs that drift and capsize. In our lab study, we found that melting makes floating ice “uncomfortable” and causes it to flip, roll and tumble.

The sequence of photographs document what happens to a cylinder of ice floating at the surface of room temperature water. The piece locks to an orientation and stays for several minutes, then abruptly rotates to a new posture, where it again locks, this process repeating until it melts away. The images are taken between flips. Variable-intensity backlighting and refraction through the ice help to show its faceted shape and surface patterning.

The central photo captures the flows beneath the iceberg that are driven by temperature and density differences. We use the color Schlieren method that visually amplifies variations in refractive index. The cold, dense fluid falls in drips and plumes that scar the ice surface with wavy patterns. Gradual melting of the undersurface leaves the body increasingly top heavy, causing it to lose gravitational stability and later roll over.